Mobile phones with digital cameras are broadly available in every worldwide market. According to market statistics and forecasts, by 2018, annual smartphone shipments are expected to grow to 1.87 billion units; over 80% of all mobile phones will be arriving to customers with embedded digital cameras. New shipments will expand the already massive current audience of approximately 4.3 billion mobile phone users and 6.7 billion mobile subscribers; they will also update mobile phones currently used by the subscribers.
The volume of photographs taken with phone cameras is growing rapidly and begins to dominate online image repositories and offline storage alike. According to Pew Research, photographing with phone cameras remains the most popular activity of smartphone owners. InfoTrends has reported that the annual volume of digital photographs has nearly tripled between 2010 and 2015 and is expected to reach 1.3 trillion photographs in 2017, while the number of stored photos in 2017 may approach five trillion. It is projected that of the total 2017 volume of digital photographs, 79% will be taken by phone cameras, 8% by tablets and only 13% by conventional cameras. On social photo sharing sites, the volume of images taken with smartphones has long exceeded the quantity of photographs taken with any other equipment.
Hundreds of millions smartphone users are blending their everyday mobile work and home digital lifestyles with paper habits. Paper documents retain a significant role in the everyday information flow of business users and households. Digitizing and capturing of paper based information has further progressed with the arrival of multi-platform cloud-based content management systems, such as the Evernote service and software developed by Evernote Corporation of Redwood City, Calif., the Scannable software application for iPhone and iPad by Evernote and other document imaging software. These applications and services offer seamless capturing of multiple document pages and provide perspective correction, glare mitigation, advanced processing, grouping and sharing of scanned document pages. After the documents are captured and stored, the Evernote software and service further enhance user productivity with advanced document search capabilities based on finding and indexing text in images. Additionally, photographs that include images without significant amounts of surrounding text may be enhanced using advanced color correction methods for storage, sharing, printing, composition of documents and presentations, etc.
Determination of a relevant processing path for a scanned document page presents a challenging aspect of smartphone based scanning solutions. After initial pre-processing steps for a photographed page image have been accomplished (which may include glare mitigation, perspective and other spatial corrections, etc.), there may be several different directions for further image processing. Pages with significant amounts of text may be optimized for text retrieval and search purposes; accordingly, processing algorithms may increase contrast between the page text and the page background, which in many cases may result in a black-and-white image where the text is reliable separated from the rest of the image. On the other hand, images taken for aesthetical, illustration and presentation purposes typically undergo color correction and color enhancement steps that enrich color palette and attempt to adequately reproduce lighting conditions and provide a visually pleasing balance between contrasting and smooth image areas. Therefore, errors in determining adequate processing paths for captured images may lead to expensive and unnecessary post-processing diagnostics, double processing steps and an undesired need for user intervention.
Accordingly, it would be useful to develop efficient mechanisms for quick automatic identification of document page photographs as text vs. image types at early processing steps of automatic mobile image scanning and processing.